RFID-based positioning system for indoor environments

Abstract

Particular embodiments described herein include an apparatus for providing RFID-based locations for items located in an indoor environment including an RFID scanner to transmit interrogating RFID signals and to receive RFID identifiers for RFID tags, the RFID tags being affixed to the items in the indoor environment. The apparatus can additionally include an indoor location tracking device to determine a current location of the apparatus within the indoor environment, wherein the apparatus is mobile and configured to be moved throughout the indoor environment. The apparatus can further include an RFID-location processor to receive RFID data from the RFID scanner and location data from the indoor location tracking device, correlate portions of the RFID data with portions of the location data, and generate RFID-based location data for the items located in the indoor environment based, at least in part, on the correlated portions of the RFID data and the location data.

What is claimed is: 
     
       1. A method for providing RFID-based locations for items located in an indoor environment, the method comprising:
 receiving, by a processor of a RFID-based location apparatus from an RFID scanner that is part of the RFID-based location apparatus, RFID data,
 wherein the RFID-based location apparatus comprises:
 (i) the RFID scanner configured to transmit interrogating RFID signals and to receive a plurality of RFID identifiers for RFID tags that are within range of the RFID scanner, wherein the RFID tags are affixed to the items located in the indoor environment, wherein the plurality of RFID identifiers are received within a period of time of each other, 
 (ii) an indoor location tracking device configured to interact with an indoor positioning system to determine a current location of the RFID-based location apparatus within the indoor environment, wherein the RFID-based location apparatus is mobile and configured to be moved throughout the indoor environment as the plurality of RFID identifiers are received by the RFID scanner within the period of time and 
 (iii) the processor in network communication with the RFID scanner and the indoor location tracking device, 
 
 wherein the RFID data comprises a plurality of signal strength readings for each of the plurality of RFID identifiers at different locations in the indoor environment, the plurality of signal strength readings for each of the plurality of RFID identifiers comprising time series data within the period of time of each other, 
 wherein the time series data for each of the RFID identifiers is generated from the RFID scanner being physically moved around different locations near the RFID identifier over the period of time, 
 
 receiving, by the processor from the indoor location tracking device, location data; 
 correlating, by the processor, portions of the RFID data with portions of the location data, 
 identifying, by the processor and for each of the RFID identifiers, a current location for the RFID identifier using the correlated RFID and location data, wherein the current location of the RFID identifier in the indoor environment is selected from among the different locations for the RFID identifier in the correlated RFID and location data, wherein the current location is selected as a having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier, and 
 generating, by the processor, RFID-based location data for the items located in the indoor environment based, at least in part, on the identified correlated portion of the RFID data and the location data, wherein generating the RFID-based location data for the items comprises identifying the current location in the indoor environment corresponding to the relative maximum signal strength for each of the RFID identifiers. 
 
     
     
       2. The method of  claim 1 , wherein:
 the time series data comprises the plurality of RFID identifiers detected by the RFID scanner with corresponding RFID timestamps identifying times at which the RFID scanner detected each of the plurality of RFID identifiers while the RFID scanner is being physically moved around the different locations near the RFID identifier over the period of time, and 
 the location data comprises a time series of the current location for the RFID-based location apparatus with corresponding location timestamps identifying times at which the indoor location tracking device determined each of the current locations. 
 
     
     
       3. The method of  claim 2 , wherein correlating portions of the RFID data with the portions of the location data comprises:
 determining a correlation between the RFID timestamps and the location timestamps; and 
 pairing the portions of the RFID data and the portions of the location data based on the correlation. 
 
     
     
       4. The method of  claim 3 , further comprising:
 determining whether a frequency for the RFID data is less than a frequency for the location data and 
 based on a determination that the frequency for the RFID data is less than the frequency for the location data:
 identifying groups of the location data that correspond to individual instances in the RFID data; 
 determining combined locations for each of the groups of location data; and 
 pairing the combined locations with the individual instances of the RFID data. 
 
 
     
     
       5. The method of  claim 4 , wherein the combined locations for each of the groups of location data comprise an average of locations corresponding to the group. 
     
     
       6. The method of  claim 4 , wherein the combined locations for each of the groups of location data comprise a median of locations corresponding to the group. 
     
     
       7. The method of  claim 4 , wherein the combined locations for each of the groups of location data comprise a mode of locations corresponding to the group. 
     
     
       8. The method of  claim 3 , further comprising:
 determining whether a frequency for the RFID data is greater than a frequency for the location data and 
 based on a determination that the frequency for the RFID data is greater than the frequency for the location data:
 identifying groups of the RFID data that correspond to individual instances in the location data; 
 consolidating each of the groups of RFID data to a singular instance of RFID data; and 
 pairing each of the consolidated groups of RFID data with individual instances of the location data. 
 
 
     
     
       9. The method of  claim 1 , wherein identifying, by the processor and for each of the RFID identifiers, a correlated portion of the RFID data and the location data amongst the correlated portions having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier comprises:
 for each RFID tag, selecting one or more correlated RFID and location data records having a relative maximum signal strength among all correlated RFID and location data records for the RFID tag; and 
 determining a location for the RFID tag based, at least in part, on the selected one or more data records. 
 
     
     
       10. The method of  claim 9 , further comprising:
 determining whether (i) more than one of the data records from the correlated RFID and location data records has the maximum signal strength or (ii) more than one of the data records is within a threshold value of the maximum signal strength and 
 in response to determining that more than one of the data records has the maximum signal strength or is within the threshold value of the maximum signal strength, determining the location for the RFID tag based on a combination of locations from the more than one data records. 
 
     
     
       11. The method of  claim 10 , wherein the combination of locations from the more than one data records comprises an average of the combination of locations. 
     
     
       12. The method of  claim 10 , wherein the combination of locations from the more than one data records comprises a centroid of the combination of locations. 
     
     
       13. The method of  claim 10 , wherein the combination of locations from the more than one data records comprises a weighted average of the combination of locations, the weighted average being based on corresponding signal strengths for the more than one data records. 
     
     
       14. The method of  claim 1 , wherein identifying, by the processor and for each of the RFID identifiers, a correlated portion of the RFID data and the location data amongst the correlated portions having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier comprises:
 accessing location confidence values for the location data; 
 for each RFID tag, selecting one or more correlated RFID and location data records having a relative maximum signal strength and relative maximum location confidence value among all correlated RFID and location data records for the RFID tag; and 
 determining a location for the RFID tag based, at least in part, on the selected one or more correlated RFID and location data records. 
 
     
     
       15. The method of  claim 14 , wherein the relative maximum location confidence value exceeds a threshold confidence range. 
     
     
       16. The method of  claim 14 , wherein the indoor location tracking device is further configured to detect the location confidence values and to include the location confidence values as part of the location data. 
     
     
       17. The method of  claim 1 , wherein:
 the indoor environment includes buffers between first locations and second locations in the indoor environment, the first locations including a sales floor and the second locations including stock rooms, and 
 the method further comprises discarding, by the processor, at least one of the RFID data and the location data based on a determination that the at least one RFID data and the location data is associated with a location in the indoor environment that includes at least a portion of the buffers. 
 
     
     
       18. A method for providing RFID-based locations for items located in an indoor environment, the method comprising:
 transmitting, by an RFID scanner that is part of a RFID-based location apparatus, interrogating RFID signals; 
 receiving, by the RFID scanner, a plurality of RFID identifiers for RFID tags that are within range of the RFID scanner, wherein the RFID tags are affixed to the items located in the indoor environment; 
 determining, by an indoor location tracking device that is part of the RFID-based location apparatus, a current location of the RFID-based location apparatus within the indoor environment based on interactions between the indoor tracking device and an indoor positioning system, wherein the RFID-based location apparatus is mobile and configured to be moved throughout the indoor environment as the plurality of RFID identifiers are received by the RFID scanner within the period of time; and 
 generating, by an RFID-location processor that is part of the RFID-based location apparatus, RFID-based location data for the items located in the indoor environment, wherein the generating includes:
 receiving, by the RFID-location processor, RFID data from the RFID scanner and location data from the indoor location tracking device, wherein the RFID data comprises a plurality of signal strength readings for each of the plurality of RFID identifiers at different locations in the indoor environment, the plurality of signal strength readings for each of the plurality of RFID identifiers comprising time series data within the period of time of each other, wherein the time series data for each of the RFID identifiers is generated from the RFID scanner being physically moved around different locations near the RFID identifier over the period of time, 
 correlating, by the RFID-location processor, portions of the RFID data with portions of the location data, 
 identifying, by the RFID-location processor and for each of the RFID identifiers, a current location for the RFID identifier using the correlated RFID and location data, wherein the current location of the RFID identifier in the indoor environment is selected from among the different locations for the RFID identifier in the correlated RFID and location data, wherein the current location is selected as a having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier, and 
 generating, by the RFID-location processor, the RFID-based location data for the items located in the indoor environment based, at least in part, on the identified correlated portion of the RFID data and the location data, wherein generating the RFID-based location data for the items further comprises identifying the current location in the indoor environment corresponding to the relative maximum signal strength for each of the RFID identifiers. 
 
 
     
     
       19. A device for providing RFID-based locations for items located in an indoor environment, the device comprising:
 an RFID scanner configured to transmit interrogating RFID signals and to receive a plurality of RFID identifiers for RFID tags that are within range of the RFID scanner, wherein the RFID tags are affixed to the items located in the indoor environment, wherein the plurality of RFID identifiers are received within a period of time of each other; 
 an indoor location tracking device configured to interact with an indoor positioning system to determine a current location of the device within the indoor environment, wherein the device is mobile and configured to be moved throughout the indoor environment as the plurality of RFID identifiers are received by the RFID scanner within the period of time; 
 processor in network communication with the RFID scanner and the indoor location tracking device, wherein the processor comprises memory storing instructions that are executed by the processor, wherein executing the instructions causes the processor to perform operations comprising:
 receiving, from the RFID scanner, RFID data, wherein the RFID data comprises a plurality of signal strength readings for each of the plurality of RFID identifiers at different locations in the indoor environment, the plurality of signal strength readings for each of the plurality of RFID identifiers comprising time series data within the period of time of each other, wherein the time series data for each of the RFID identifiers is generated from the RFID scanner being physically moved around different locations near the RFID identifier over the period of time; 
 receiving, from the indoor location tracking device, location data; 
 correlating, portions of the RFID data with portions of the location data; 
 identifying, for each of the RFID identifiers, a current location for the RFID identifier using the correlated RFID and location data, wherein the current location of the RFID identifier in the indoor environment is selected from among the different locations for the RFID identifier in the correlated RFID and location data, wherein the current location is selected as a having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier; and 
 generating RFID-based location data for the items located in the indoor environment based, at least in part, on the identified correlated portion of the RFID data and the location data, wherein generating the RFID-based location data for the items comprises identifying the current location in the indoor environment corresponding to the relative maximum signal strength for each of the RFID identifiers. 
 
 
     
     
       20. The device of  claim 19 , wherein identifying, by the processor and for each of the RFID identifiers, a correlated portion of the RFID data and the location data amongst the correlated portions having a relative maximum signal strength amongst the plurality of signal strength readings in the time series data for the RFID identifier comprises:
 accessing location confidence values for the location data; 
 for each RFID tag, selecting one or more correlated RFID and location data records having a relative maximum signal strength and relative maximum location confidence value among all correlated RFID and location data records for the RFID tag; and 
 determining a location for the RFID tag based, at least in part, on the selected one or more correlated RFID and location data records.